¹Ryota Fukai, ²Yusuke Takeda, ^3,4Yuki Masuda, ^4,5Daiki Yamamoto, ⁶Yasuhiro Iba, ⁶Shintaro Sasaki, ⁶Shin Ikegami, ⁷Aya Kubota,⁸Reo Sato, ^1,8Tomohiro Usui
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2025.116648]
¹Astromaterial Science Research Group, Japan Aerospace Exploration Agency
²Scattering and Imaging Division, Japan Synchrotron Radiation Research Institute
³Department of Earth and Planetary Sciences, Institute of Science Tokyo
⁴Centre for Star and Planet Formation, Globe Institute, University of Copenhagen
⁵Department of Earth and Planetary Sciences, Kyushu University
⁶Department of Earth and Planetary Sciences, Hokkaido University
⁷Research Institute for Geo-Resources and Environment, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology
⁸Department of Earth and Planetary Science, The University of Tokyo
Copyright Elsevier

The evolution associated with coagulation/fragmentation processes of dust to planetesimals in the protosolar disk is the critical phase of planet formation in the Solar System. The meteoritic components, such as calcium‑aluminum-rich inclusions (CAIs), will provide essential constraints on the coagulation/fragmentation process in the early stage of the disk. We applied the bright-field grinding tomography method to an Allende meteorite (CV3) slab to visualize the coarse-grained CAIs (CG-CAIs) in a colorized 3D model with high spatial resolution. We found four mm-scale CG-CAIs that experienced deformation and/or fragmentation processes within ~1.8 × 103 mm3 Allende slab. An angular-shaped CG-CAI’s surface showed the anisotropy of red-gray and white sides, which suggests that the fragmentation results in the loss of the primitive Wark-Lovering rim. We also found a vesicular-shaped CG-CAI, which indicates that the fracturing and complex formation process of this CG-CAI likely proceeded prior to the accretion of the Wark-Lovering rim. Our observations reveal that the fragmentation of Allende CAIs occurred during the parent body accretion stage and also in the protosolar disk.